Alternating-current meter



Dec. 9 v 1,519,098

. L. ADERT ALTERNATING CURRENT MET-ER Filed Aug. 10 1920 Inventor Lc0aold.dder

Patented Dec. 16, 1924.

LEOPOLJ ADEB.T, OI BERLIN, GERMANY.

anrmnrmwcummnr METER.

,Application filed nzut 10, mo. Serial 172. 402,737.

To dll whom it may concern: Y V Be it known that:I, Lnoronn ADERT, a

citizen of Germany, and resident of Berlin,

Germany,have invented, a certainnew and l useful Improved Alternatingurrent Meter (for whichl havefiled applications in Germany, December 31, 19'18, Patent No; 321,168 Holland, May 5, 1920, Patent No. 9,141; Hungary, May 31, 1920, Patent No. 78,924;

Denmark, August20, 1920, Patent No. 31,226 England,July 12, 1920, Patent No. 151,245; Belgium, June 30, 1920, Patent No. 288,100;

France, July 1, 1920, Patent No. 518,495,

Italy, une 29,1920, patente not yet granted; Sweden, June 4, 1920, Patent No. 55,092;

. Switzerland, June 8, 1920, Patent No. 89,572;

Spain, June 30, 1920,'Patent No. 74,272; the outer leg. In order to: provide for exact Austria, J une 82 1920, Patent No. 86,335;

Czechoslovakia, June 21,1920, Patent No. 6612), of which the followingis a specification. Y

The present invention broadly refers to alternating current meters and it has for-its object to provide a driving system for electrieal meters constructed on the, Ferraris principle for measuring alternatin and three phase currents, with a considerab e turning moment, low consumption in the shunt circuit, and adequate roportionality for all loads throughout tiie whole range of measurement.

The original method of carrying the principle into effect is represented by the known driving system comprising a ressure or field magnet core in the sha e o e a C and a U shaped electro-magnet, or example, similar to those described in German patent specifications 215,194 and 295,665. In the drawings aifixed to this specification and forming part thereof, a device embdying my invention is illustrated diagrammatically by way of example.

In the drawings Figure 1 is a side elevation of the'pressure me net core, While igures 2 and 3 are a side elevation and front elevation respectively of the rotor and the magnets combined therewith;

In accordance with this present invention, a third leg is provided on the pressure magnet core, so as to obtain an m-shaped upper part. The free end of the leg which em-' braces the drivin disc is made to extend in front of the thir leg so as to constitute an Opposing pole to it. a is the three-legged pressure magnet, with its winding o provided on the middle leg. The rotor c is located in'the air-gap between the legs which are of ,equal length and the leg which extends past their ends. The said rotor is traversed by the lines of force of the. pressure magnet at two points spaccd sufliciently apart, fromeach other tope rmit two polar fields to act upon the driving disc in opposite direc' tions. Their power ratio can be va ried Within certain limits by means of a magnetic bridge piece d located between thetwo legs of substantially equal length. This maybe accomplished for example bymoving the said bridge piece nearer the middle or nearer compensation and to ensure .a; 90" phase difference between the maincurrent field and the pressure field.anadjpstable sheet metal piece IL made of copper. or,of some other conductive material is provided, the said sheet being, whenever necessary, introduced into the a1r gap between the upper leg of the magnet coreandthe magnetic bridge piece d.

The U-shaped core e .0f the series-cil. f is placed on the side of the rotor opposed to the pressure magnet. The result is that two current actuating fields of o posite sign are formed, one on each side o the leg of the pressure inagnet carrying the pressure c'oil.

'As that leg of the pressure magnet embracing the rotor rovides for a good return circuit for the ow of magnetic lines of orce, the driving action of the pressure field suifices to permit a sufiiciently high torque to be obtained by use of the main current winding generally employed for any driving sys tem for meters.

Now whenever the number of turns of the main current coi1 is increased, more powerful current fields and, as a result, a higher torque are secured. However, under ordi nary circumstances the number of turns could not be increased because, owing to the su ersaturation of the iron core, which takes p ace prior to reaching the upper load limit of the meter, the registration Will decrease in the upper range of the measuring action of the meter. This drawback is eliminated by exerting on the rotor a driving action in the opposite direction by aid of the third leg w ich, according to the invention, has been added to the pressure magnet in consequence A As a result he correetmg of the mutual action of the current field and the field of the third leg of the pressure magnet.

The two pressure fields being spaced apart from each other, each of the two legs of the U-shaped main current core is provided with angular iron members g and g these members forming the main Currentdriving fields of different signs on either side of the pressure field and producing the counter torque.

Now, the partial counter torque, which is used as a correcting device for providing com ensation :Eor the defective indications of tlie meter, 0 eratesby reason of a considerable r fall, w ich ocurs in the magnetiz ing curve of the -counter torque system, Whenever the loadis 'bein'g increased, in comparison withthe magn'etizing curve of the forward tor ue system, since the cross sectionalarea o iron of the two"angular pieces g and ghas been so determined and so formd, that they become magnetically s&turated when the meter is running at-' half load, so that on a f urther increase in" the load, there is -no sub s'tntial further in-' crease, in the counter torque, which therefore remains practically constant. A 7

device effects a decrease in the 'indicsitions given by the meter within the lower range of measure ment, and this corisequently permits to se-" cure a suificient 'proportionality of the data indicated by the 'saidmeter for all loads.

" dially juxtapsed legs forming part of I claim: V

1. An electriccurrent meter, comprising a rotor and a pressure magnet 'corefidisposed radially with regard to said rotor, two rasaid 'core'and extending substantially at an angle to said rotor, and a third angularle on said core part of said third leg exten ing in paralle ,another part at angles to said two legs substantially in parallel with and close to the opposite side of said rotor.

2. An -alte'rnating' current meter 'comprising a rotor,- asbstantially m-shaped ressure magnet With an air gap partly em racing said rotor-and means adapted to cooperate with said magnet for creating two pole fields .separated from each other and actin on said rotor in opposite senses.

3. n altern'ating current meter comprising a rotor, a substantially m-shaped pres: sure magnet with*an air ga partly embracing said rotor, means a apted to cooperate with said magnet for creating two pole fields 'sep'arated from each other'and acting on said rotor in opposite Sehses and a magnetic bridge displa'cegbl'y disposed be' tween the parts of 'said magnetwhieh create the pole-fields r 4. An alternatingurrent meter-compris: ing a rotor, a" substantiallyfineshaped pressure magnet With fan air ga p artlyembracingf said rotor, means a apted**to coopeiatewith said magret for creating.two

pole fields separated from each other and acting on said rotor in o osite senses; a -mgnetic bridge displacea iy disposd be tween the parts of said magnet which create the pole fields, and a piece of. Conductive sheet metal adjstably arranged'in the"air gap betw'een said bridge and "one of Said parts. r

5. In an 'altemiating current meter a pressure magn'et core, comprisin'g an mshaped portion,= a transverse leg attached to an end of and eXtending below said portion, a'U-shaped main current magne't core em bracing said trahsverse leg and an angular piece of iron-'arranged on either leg of said U-shaped core,

- 'LEOPOLD'ADERT. 

